Sleep is an important element in staying healthy, and being aware of one's sleep patterns is important from the viewpoint of maintaining good health.
Polysomnography (PSG) is a typical method of measuring sleep patterns. Polysomnography is one method of examination used to diagnose sleep disorders, and involves measuring the brainwaves of the person being evaluated, and checking the depth of sleep based on changes in the brainwaves.
A simple method involves measuring temporal changes in the body motion of the person being evaluated using sensors that are arranged under the bedding, and judging the state and quality of sleep of the person being evaluated based on the measurement results, as disclosed in JP 2009-160001A (hereinafter, Patent Literature 1) and JP 2008-142238A (hereinafter, Patent Literature 2), for example.